Safety paper and method of making same



Sept. 6, 1938. F. L. SIMONS ET AL SAFETY PAPER AND METHOD OF MAKING SAME Filed Nov. 21

d VENTORS BY 5 f ATTORNEYS Patented Sept. 6, 1938 UNITED STATES PATENT OFFICE Francis L. Simons, Needham, and Mark W. Weiss,

Boston, Mass, Son, Nutley, N.

assignors to George La Monte & J., a corporation of New Jersey Application November 21, 1936, Serial No. 112,009

11 Claims.

This invention relates to safety paper and method of making safety paper. This invention relates particularly to paper of the type which by appropriate treatment can be tested to determine its authenticity. According to this invention, a safety paper is afforded which, when treated with a liquid, as, for example, by moistening a portion of the same With water, will give visible evidence of its authenticity.

Safety paper of the type to which this invention relates is suitable for many purposes. For example, safety paper of the type to which this invention relates is adapted for use in connection with labels, tickets, wrapping papers, boxboard.

- for cartons and the like so that the genuineness thereof may be determined. To illustrate, safety paper embodying this invention is adapted for use as labels for beverages. In connection with the sale of alcoholic beverages, certain unscrupulous sellers have in the past manufactured counterfeit labels bearing the names of wellknown liquors demanding a relatively high price and have applied them to inferior and inexpensive liquors. According to the present invention, safety paper is afforded which enables one to determine in a convenient, positive and simple manner whether such labels, for example, are genuine or counterfeit. Merely by applying a liquid, e. g., water, to the label or to a portion of the label, visible evidence of the genuineness of the label is at once apparent. After the label has dried again, it preferably assumes its original appearance.

It is a purpose of the present invention to af- 3 ford an improved safety paper of the character above mentioned and an improved method for the manufacture of such safety paper.

It is a feature of safety paper embodying this invention that it comprises sheet material superficially presenting indicia which are of a lighter shade of color in comparison with the color of the surface of said sheet and which are adapted to have the permeability thereof to light increased to a substantial extent upon the application of a 1iquid,.e. g., water, thereto so as to become of decreased visibility in comparison with the background thereof upon application of said testing liquid.

In the practice of this invention, the surface 11f the sheet material is of a color other than white and the indicia are applied thereto using a material which is of a lighter shade of color by virtue of being of a substantially white color or of a lighter shade of a different color from the surface of the base sheet or of a lighter shade of the same color as the surface of the base sheet. Preferably, the indicia are substantially white. The indicia which are applied to the base sheet are of such character as to appear prominently on the sheet when the sheet is dry and to become substantially less discernible after a liquid has been applied thereto because of their increased permeability to light upon application of the testing liquid.

The utility of a safety paper embodying this invention is apparent. Such safety paper in its ordinary dry condition will, have certain indicia which appear prominently thereon. These indicia may be in the form of conventional appearing legends. When it is desired to test the safety paper to determine its authenticity, all that is required is to apply a small amount of liquid to the paper as by applying a small amount of water thereto with a sponge or even with the end of the finger. If the paper is genuine, the indicia will either substantiallydisappear or will become of strikingly modified appearance. If the paper is counterfeit, the indicia will not exhibit this striking change. Safety paper embodying this invention may not only bear indicia having the characteristic aforesaid of becoming changed in appearance upon application of a liquid thereto, but may also carry permanent printing or permanent ornamental figures or both as may be desired.

Further purposes, features and advantages of this invention will be apparent from the following description of this invention in connection with the accompanying drawing which shows an illustrative embodiment thereof, wherein:

Figure 1 is a plan view of safety paper embodying this invention when dry, and

Fig. 2 is a view of the safety paper shown in Fig. 1, after a liquid has been applied to a portion of the safety paper.

In the drawing, a safety invention is indicated paper embodying this generally by the reference character ID. The safety paper comprises a sheet ll of some suitable material such as a desired paper stock. The characteristics of the sheet Il may be selected as desired. For example, if a thin paper is desired, the sheet H can be made appropriately thin. If, on the other hand, heavy material such as boxboard, is desired, sheet It may be made of the desired heaviness and strength. The manufacture of sheet materials having such characteristics is well known in the art. Applied to the surface of the sheet H are indicia l2 which are of a color that contrasts with the color of the surface of the sheet II. In the embodiment shown in Fig. 1, the sheet H is preferably of a color other than white, such as a primary color, e. g., blue. For purposes of affording further specific illustration, the indicia I2 are applied using a material which is white when the safety paper is in a dry condition. The safety paper may include printed matter such as the legend or legends I3 and ornamentalfigure or figures 14 (although permanent all-over solid color printing is preferably 2 not employed.) Of course, any variations in the design and significance of the legends or figures may be selected as desired.

In Fig. 2, the safety paper is shown after a liquid has been applied to a portion thereof. The indicia l2 which is applied to the safety paper in this embodiment is composed of a material such as a mixture of casein and clay of the type which is commonly used in the finishing of book papers and printing papers. For example, the indicia I2 may be applied using a mixture containing one part of casein and four parts of clay. Such a mixture, while appearing of a distinct white color when dry, is adapted to have the permeability thereof to light increased to a substantial extent when water is applied thereto. Consequently, as shown in Fig. 2, after water is applied to the safety paper, e. at the area enclosed in dotted lines, the indicia E2 in such portion becomes substantially less prominent. If the amount of material used in printing the indic-ia l2 upon the paper is not too great, these indicia will, as a result of moistening with water, become substantially non-discernible. This affords visible evidence of a striking character when water is applied to the safety paper that the paper is genuine. After the applied water evaporates, the safety paper will assume its original appearance. The test can be repeated as often as desired.

Safety paper embodying this invention may be made by first forming the sheet I l of any desired material. This sheet is preferably colored, using, for example, some coloring matter such as an aniline dyestuff of which many are well known for use in paper-making or some insoluble pigmerit such as those used in paper-making, e. g., ultra-marine, carbon black, Prussian blue, burnt umber, and the like. The coloring matter may be incorporated throughout the paper or may be applied merely to the surface thereof to which the indicia are to be applied. After the base sheet has been formed, the indicia l2 can be placed on the colored surface thereof as by a printing operation which is like an ordinary printing operation except as to the character of the material deposited on the safety paper. If desired, the safety paper can be subjected to a subsequent printing operation or operations so as to cause the paper to bear desired permanent legends and ornaments such as the legends l3 and the ornamental figures M which are shown in the drawing. These legends and ornaments can be ap plied using ordinary inks and the like as is well known.

, Mixtures of casein and clay have the property when dry of being substantially impermeable to light and of becoming highly permeable to light when moistened with water. In addition to mixtures of casein and clay, other compositions suit able for a similar purpose in the practice of this invention may be used. Thus, instead of casein, other materials may be used, such as albumin, glue, rosin dissolved in alkali, gum, arabic and tapioca gum, as well as various other albuminous substances and gums. Instead of clay, other finely-divided mineral fillers may be used such as lithopone, barytes, calcium carbonate, silica and asbestine. Materials of the character aforesaid result in a white or nearly white material with which to form the indicia which are subject to change upon being treated with a liquid. If .a color other than white is desired to be used as. the indicia, a coloring matter can be incorporated such as a dye or a pigment of a color other than white, sufficient of the coloring matter being used to secure a desired light shade of color.

When binders of the character above mentioned are employed, it is frequently desirable to employ a hardener or insolubilizer such as formaldehyde, alum, zinc sulphate, aluminum acetate or tannic acid that is applied to the binder either before or after formation of the indicia. When glue or albumin is used ammonium or potassium dichromate may be employed for this purpose. The hardeners or insolubilizers tend to render the binder part more permanent and make the indicia more resistant to smudging upon the application of a testing liquid, e. g. water. Especially when rosin dissolved in alkali is used, it is desirable to employ a hardener. Moreover, other materials may be used to constitute indicia which indicia are of such character that, because of their porosity, absorptiveness or the like are penetrable by the testing liquid without becoming unduly softened and which indicia contain particles that when moistened with the testing liquid become more transparent or translucent.

It is normally preferable that the material used in the indicia be of a character which is adapted to have its permeability to light increased when moistened with water. However, other liquids than water may be used by which to test the paper. Thus saliva is to be regarded as the equivalent of water. Likewise, various aqueous solutions of acids or salts may be applied as the testing liquid. By way of further illustration, where the indicia are composed of a mixture of binder and filler, e. g., casein and clay, other liquids than water may be used to increase the permeability of the indicia to light such as ethyl, methyl and butyl alcohols, ethyl acetate, carbon tetrachloride, benzol, turpentine and the like. While an oil such as a light mineral oil may be used, such a liquid has the disadvantage that it is non-volatile and leaves a permanent mark on the paper. Preferably, a volatile liquid such as water, alcohol, carbon tetrachloride or the like is used which quickly evaporates after the paper has been tested by application of such liquid thereto. It is also preferable that the index of refraction of particles of filler material and of the testing liquid be as nearly as possible the same, as the transparency of the indicia can be increased to a greater extent when a testing liquid of such character is selected. However, even when there is quite a wide difference between the index of refraction of the filler particles and the index of refraction of the testing liquid very pronounced increase in transparency of the indicia can be obtained.

As aforesaid, it is usually desirable that the indicia which are affected by application of water thereto be white in color and that the base sheet be of a color which differs substantially from white. However, it is apparent that certain features of this invention may be availed of when the indicia are colored but are of a substantially lighter shade of color than the color of the base sheet. The colors of the indicia and base sheet may be different, e. g., the base sheet may be blue and the indicia may be a light shade ,of red. Moreover, the base sheet and indicia may be different shades of the same color, e. g., the base sheet may be a dark blue while the indicia may be of a substantially lighter shade of blue and such arrangement is preferable to using a lighter shade of some other color as more complete disappearance of the indicia is possible when a testing liquid is applied to the paper.

With paper embodying this invention, it is ap parent that a plurality of spaced indicia are afforded such as legends and the like which enable the paper to be tested in the manner aforesaid, namely, by treatment with a testing liquid to accomplish substantial decrease in prominence of the indicia, wherever the testing liquid is applied.

While it is desirable to have the indicia of such character as to substantially disappear on the application of a testing liquid thereto such substantially complete disappearance is not necessary. Thus according to this invention the indicia may merely become less prominent to a substantial and noticeable extent, upon application of a testing liquid, e. g., water, thereto.

While this invention has been described in connection with certain illustrative embodiments thereof, it is to be understood that this has been done merely for the purpose of afiording illustrations thereof, and that the scope of this invention is to be limited only by the language of the following claims.

We claim:

1. A safety paper which comprises a sheet of material presenting a surface of a color other than white and indicia overlying a plurality of portions of said surface leaving other portions exposed which indicia are of a substantially lighter shade of color with regard to the color of said surface and which indicia are composed of material adapted to have the permeability thereof to light increased to substantial extent upon the application of a liquid thereto.

2. A safety paper which comprises a sheet of material presenting a surface of a color other than white and indicia overlying a plurality of portions of said surface leaving other portions exposed which indicia are of a substantially lighter shade of color with respect to the color of said surface and which indicia are composed of material adapted to have the permeability thereof to light increased to substantial extent upon the application of water thereto.

3. A safety paper which comprises a sheet of material presenting a surface of a color other than white and a plurality of spaced indicia overlying said surface which indicia are of a substantially lighter shade of color than the color of said surface and substantially mask the color of said surface so as to be in prominent contrast to the exposed portions of said surface and which indicia are composed of material adapted to have the permeability thereof to light substantially increased upon the application of a liquid thereto so as to become substantially less prominent in contrast to the color of said surface when said liquid is applied to said paper.

4. A safety paper which comprises a sheet of material presenting a surface of a color other than white and a plurality of indicia overlying said surface in the form of legends leaving other contiguous portions exposed, which indicia are of a color selected from colors white and substantially lighter shades of the color of said surface and which indicia are adapted to have the permeability thereof to light substantially increased upon the application of a liquid thereto so as to have the prominence of the appearance of said indicia diminished to a substantial extent upon said application of said liquid thereto.

5. A safety paper which comprises a sheet of material presenting a surface of a color other than white and a plurality of indicia overlying portions of said surface in the form of legends leaving other contiguous portions exposed, which indicia are of a color selected from the colors white and substantially lighter shades of the color of said surface and which indicia are adapted to have the permeability thereof to light substantially increased upon the application of water thereto so as to have the prominence of the appearance of said indicia diminished to a substantial extent upon said application of said water thereto.

6. A safety paper which comprises a sheet of material presenting a surface of a color other than white and a plurality of spaced indicia which appear prominently on said surface of said sheet when said sheet is dry and which become substantially non-discernible after a liquid has been applied thereto due to increased permeability to light of the material of said indicia upon application of said liquid thereto.

7. A safety paper which comprises a sheet of material presenting a surface of a color other than white and a plurality of spaced indicia which appear prominently on said surface of said sheet when said sheet is dry and which becomes substantially non-discernible after water has been applied thereto due to increased permeability to light of the material of said indicia upon application of said water thereto.

8. A safety paper which comprises a sheet of material presenting a surface of a color other than white and a plurality of spaced indicia overlying said surface which are of substantially white appearance when said paper is dry and which become substantially less prominent on said paper upon application of a liquid thereto due to increased permeability to light of the material of said indicia when said liquid is applied thereto.

9. A safety paper which comprises a sheet of material presenting a surface of a color other than white and a plurality of spaced indicia overlying said surface which are of substantially white appearance when the paper is dry and which become substantially less prominent on said paper upon the application of water thereto due to increased permeability to light of the material of said indicia upon being moistened with water, said material of said indicia comprising a finely divided white powder transparent when moistened and a water-permeable binder.

10. A method of making safety paper which comprises making a sheet of material presenting a surface of a color other than white and applying indicia to the said surface in the form of a plurality of legends of a lighter shade of color than the color of said surface of said sheet when said sheet is dry, the material of said indicia being adapted to become more permeable to light upon application of a liquid thereto.

11. A method of making safety paper which comprises making a sheet of material presenting a surface of a color other than white and applying indicia to said surface of said sheet by a printing operation, said indicia being composed of a material which is of a lighter shade of color in comparison with the color of said surface of said sheet when said sheet is dry. and which is adapted to have the permeability thereof to light substantially increased upon application of a liquid thereto.

FRANCIS L. SIMONS. MARK W. WEISS. 

